PURPOSE: To develop better regimens for treatment of experimental type 2 herpes simplex (HSV2) infections in the newborn rat. PROCEDURES: Following the intracerebral or subcutaneous inoculation of HSV2 in 5 day old Wistar rats, the antiviral drug under study is administered for 5 days, beginning at 24 hours post inoculation. The efficacy of treatment is evaluated using the following criteria: a) Rate of survival, b) Titers of HSV2 in the brain and eyes of treated and control animals, c) The incidence of lesions in the brain and eyes of treated and control animals. Antiviral drugs currently under study are adenine arabinoside (ara-A); ara-A-5'-monophosphate (ara-AMP); ara-A and adenosine deaminase inhibitor pentostatin; and the immunopotentiating agent, Levamisole. We propose to expand our preliminary studies with the selective antiviral drug, acycloguanosine, or acyclovir (ACV) in the treatment of neonatal HSV2 infections. Both the parenteral and the intragastric routes of administration will be evaluated. In addition, negotiations are in progress to obtain a quantity of another selective antiviral drug, (E) 5-(2-bromovinyl)-2'-deoxyuridine (BVdU) for in vivo evaluation PART II: PURPOSE: To study the CNS and retinal changes in newborn rats inoculated intracerebrally with the HNT strain of measles virus. Aspects currently under study include age susceptibility, and the detection of the presence of virus in the eye (evaluated by electron microscopy and virus isolation).